As well as potentially paying out sacked workers' entitlements, taxpayers could be forced to stump up tens of millions of dollars to clean up the site of Clive Palmer's north Queensland refinery if the company cannot trade its way out of voluntary administration.

Key points:

The clean-up bill at the Queensland Nickel may reach $40 million, Government says

Opposition claims it could reach $300 million

Taxpayers could be forced to foot the cost of rehabilitation

The Environment Department does not hold any bond for the site

Queensland Government sources have told the ABC that the cost of remediating the Queensland Nickel site, at Yabulu, could be anywhere from $25 million to $40 million.

Former owner BHP believed the environmental clean-up cost may exceed $100 million, while the Queensland Opposition said the clean up bill could be "upwards of $300 million".

Opposition environment spokesman Stephen Bennett said taxpayers were in danger of being left to foot the cost of rehabilitation if Queensland Nickel was forced to close the refinery.

"While the state does not hold a financial assurance bond, the company's environmental authority contains conditions to ensure that rehabilitation is conducted in accordance with [department] guidelines," the department said.

The department said there were also specific requirements for Queensland Nickel to rehabilitate the refinery's huge tailings dams, which sit on the edge of the Great Barrier Reef World Heritage Area.

The dams contain high levels of ammonia and other waste.

Premier Annastacia Palaszczuk said she had asked for a report on the state of the site.

"We've already asked the Department of Environment, which comes under Resource Management, to be looking into that matter. They are taking that as a key issue and we'll be updated on that at Cabinet next Monday," she said.

Plant's closure a 'risk' to Great Barrier Reef

Townsville Mayor Jenny Hill expressed concern that there could be repercussions for the Great Barrier Reef if the plant were to close.

"While the plant is operating we have people on site and part of their role is to maintain the assets," she said this week.

"If the plant wasn't operating there is a greater risk for the reef and the environment."

Queensland's Environment Department said that under Queensland Nickel's environmental authority there were specific requirements for the company to restore disturbed areas so that they were "safe to humans and wildlife".

But the Australian Financial Review on Tuesday reported that six months before Queensland Nickel went into voluntary administration, Mr Palmer's company decided it did not need to clean up fully around the Townsville plant and only needed to restore the site so it was suitable for "industrial use".

The refinery at Yabulu has had a chequered environmental history.

Last month a magistrate ordered Queensland Nickel to stand trial for alleged breaches of environmental regulations. It is alleged one of the refinery's tailings ponds overflowed last year.

The company has indicated it will plead not guilty to the charges when the case returns to court this year.